ci: Switch to rustup over 3rd party action

Also disable Linux arm builds for now, the Docker images they use are very old.

.github/workflows/cd.yml

@@ -15,7 +15,7 @@ jobs:
     container: ${{ matrix.container }}
     strategy:
       matrix:
-        build_target: [linux-x86_64, linux-arm64, linux-armhf, macos-x86_64, macos-aarch64, windows-x86_64]
+        build_target: [linux-x86_64, macos-x86_64, macos-aarch64, windows-x86_64]
         include:
           - build_target: linux-x86_64
             os: ubuntu-latest
@@ -54,10 +54,7 @@ jobs:
             features: '--no-default-features --features rodio_backend,pancurses_backend,share_clipboard,notify'
     steps:
       - name: Install Rust toolchain
-        uses: dtolnay/rust-toolchain@stable
-        with:
-          target: ${{ matrix.target }}
-          toolchain: stable
+        run: rustup target add ${{ matrix.target }}
       - name: Install macOS dependencies
         if: matrix.os == 'macos-latest'
         run: brew install portaudio pkg-config

.github/workflows/ci.yml

@@ -13,9 +13,9 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        build_target: [linux, macos-x86_64, macos-aarch64, windows]
+        build_target: [linux-x86_64, macos-x86_64, macos-aarch64, windows]
         include:
-          - build_target: linux
+          - build_target: linux-x86_64
             os: ubuntu-latest
             artifact_suffix: linux-x86_64
             target: x86_64-unknown-linux-gnu
@@ -48,10 +48,9 @@ jobs:
             target/
           key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
       - name: Install Rust toolchain
-        uses: dtolnay/rust-toolchain@stable
-        with:
-          target: ${{ matrix.target }}
-          components: clippy, rustfmt
+        run: rustup target add ${{ matrix.target }}
+      - name: Install clippy + rustfmt
+        run: rustup component add clippy rustfmt
       - name: Install macOS dependencies
         if: matrix.os == 'macos-latest'
         run: brew install portaudio pkg-config